1. Field of the Invention
As a rule, loads carried under aircraft are provided with a pair of rings or so-called "saddles" engageable by the hook means of the carrier or suspension device.
When the hooks are operatively interconnected, the load must be presented in such a way that the two hooks engage simultaneously the two rings or saddles. However, this constraint is sometimes objectionable and therefore trigger means have been proposed in the art, wherein the hooks can be locked independently of each other so that they can be closed successively in lieu of simultaneously.
2. Summary of the Invention
The present invention relates to release or trigger means of this character. However, this invention departs from the prior art on the one hand in that it comprises an effort scaling-down kinematic chain associated with each hook, the two chains leading to a double automatic detent or interlocking device permitting the simultaneous release of the two hooks through the actuation of a known mechanical or pyrotechnical control system, and on the other hand in that it makes it possible to combine this assembly with either of the devices described and illustrated in prior patents and patent applications held or filed by the same Applicants namely permitting the equal distribution of the control force among the hooks, the centralized control of the load wedging action, and the load wedging by means of wedge members.
The above-mentioned patents and patent applications include notably the U.S. patent application Ser. No. 949 484 filed on Dec. 30, 1977 which discloses the centralized control of the wedging means by raising the hooks means, and the U.S. Pat. No. 3,954,233 which discloses the wedging means.
It is clear that the device is also applicable when the trigger system is completed by a known jettisoning or ejection system, when the loads are wedged by using screw means according to another known arrangement, and when the hook-up device comprises not only hooks disposed at the standard 14-inch spacing but also hooks disposed at the standard 30-inch spacing.
The double locking mechanism comprises two independent latch members operatively connected to the two retaining hooks, respectively, by means of a pair of effort scaling-down kinematic chains, these two latch members cooperating with a pair of pawls the simultaneous release of which is attended by the release of two latch members. These latch members are in fact released under the control of a release lever responsive to a trigger control system so as to engage at the same time both pawls for releasing the two latch members, and these latch members proper, in order to start their movement in the hook opening direction if necessary, so as to exert a "knee-breaking" action on the relevant kinematic chains.
When the release lever is tilted as a consequence of a normal power action such as the one produced by one of the known devices, the knee-breaking action exerted on the latch members and the relevant kinematic chains takes place just after the release action and its effects on the two chains are substantially simultaneous. On the other hand, when the device is unlatched very slowly, for example by using a manual control system, it may happen (unless the parts involded are machined with a high degree of precision) that one of the latch members be released shortly before the other and that the corresponding unstressed kinematic chain may thus permit the opening of the relevant hook while the other hook remains closed. In this case, serious damages might result as far as the still engaged hook means are concerned.
To avoid the risk explained hereinabove, it is one object of this invention to provide means such that it is possible to use a safety device for preventing any risk of opening one hook before the other hook is open, irrespective of the slowness of the release action and of the time elapsing from the moment the latch members are released to the moment the knee-breaking means operate efficiently. This safety device comprises means associated with the two lockable retaining latch members in order automatically to couple these two latch members at the end of the locking action and to maintain this coupling action until the two hook members open simultaneously and nearly completely. Under these conditions, the movement of one latch member to open the relevant hook involves positively the movement of the other latch member so that the two hooks can open only simultaneously.
When the load weight is particularly heavy, it causes prohibitive stress to develop in the carrier device and notably in the retaining detent means thereof, unless successive effort scaling-down devices are provided to prevent any jamming effect on the pawls during their release.
Besides, it is advantageous to scale down the efforts as close as possible to each hook, so that the dimensions of the next component elements of the kinematic chain can be reduced, the latter being consequently less loaded.
The present invention takes due consideration of these complementary data by providing a specific arrangement of the component elements of the carrier device comprising a scaling-down mechanism associated with each hook, means for coupling the two scaling-down mechanisms with each other, and the detent-positioning of this coupling means through the medium of a third common scaling-down device.
The preliminary manual cocking, i.e. the detent-positioning of the coupling provides at the same time the simultaneous resetting of the first pair of effort scaling-down mechanisms associated therewith. Under these conditions, the hooks are free with respect to the retaining mechanism and can pivot to their closed position independently of each other under the action of the load rings when the load is fixed in position.
At the end of the closing movement, each hook is brought separately into locking engagement with the pawl of the effort scaling-down device associated therewith.
The third common scaling-down action further assists in reducing the efforts exerted on the common retaining pawl. The upward movement of this common pawl is necessarily attended by the simultaneous opening of the hook means, as will be explained presently.
Various forms of embodiment of the independent-hook and automatic-locking device according to this invention for loads carried or suspended under aircraft will now be described in detail with reference to the accompanying drawings.